I received a used pool for free in the classifieds. We have had the pool, a 27' round Swim N Play extruded aluminium, for about 7-8 years. Swim N Play said they stopped making the model we have about 10 years ago, so the pool is old. Fortunately they still make replacement parts.

The first thing I would do is find the make and model of the pool and find out any info that you can about it. The company's website may have info in the form of installation manuals, packing sheets and available replacement parts.
If you cannot find the info you need because it's an off brand or the company no longer exists, step away.

I have found everything I need on the internet website of Swim N Play and they return emails promptly. It's not hard to dissassemble a pool, nor to put it back together, but a set of instructions for your model will go a long way to alleviate headaches. Perhaps you neighbors held on to their paperwork and if it was purchased locally may have contact info for the local dealer for that brand of pool.